As you can see, while they enjoyed robust growth in the days before the bubble popped, both the Czech Republic and Hungary have been treading economic water for quite awhile.

FORBES: If You're Looking for Economic Stagnation Don't Look at Russia, Look At Hungary and the Czech Republic

It is thought that recent high rainfall had displaced the CO2-rich water at the bottom, releasing a massive bubble of carbon dioxide gas from the lake in a natural phenomenon now referred to as "lake overturn".

BBC: 1986: Hundreds gassed in Cameroon lake disaster